There have been many efforts focused on the cooling of hot gas path components of gas turbine engines, typically resulting in some loss of efficiency. Closed-loop steam cooling of, for example, stator vanes of the first-stage nozzle in a gas turbine engine extracts heat from the vanes which is transferred to the cooling steam. During this heat energy exchange process, turbine heat energy given up to the steam as a result of cooling the vanes is manifest as a parasitic penalty or loss to combined cycle efficiency.
It would therefor be desirable to provide a cooling circuit for steam-cooled gas turbine components that recovers at least a portion of the heat energy otherwise lost to the cooling process.